1. Field of the Present Invention
The present invention relates to a relative positioning and tracking process, and more particularly to a process and system for three-dimensional (3D) relative positioning and tracking, utilizing a range image and reflectance image producer, including a laser dynamic range imager (LDRI), wherein a complete suite of unique 3D relative positioning and tracking algorithms and processing methods, including cross plane correlation, subpixel tracking, focal length determination, Kalman filtering, and orientation determination, is employed to take full advantage of the range and reflectance information provided by LDRI to provide relative position and orientation of a target with respect to the LDRI""s carrier.
2. Description of Related Arts
Relative positioning and tracking are critical in some applications involving structural-dynamic measurements, automated navigation, tracking of projectiles, munition guidance, collision avoidance, surveillance of military subjects, target recognition, metrology, robotic vision, and highly accurate automated docking of unmanned micro shuttles to the docking module of satellites in orbit.
The Laser Dynamic Range Imager (LDRI) was developed by the Sandia National Laboratories to take care of the illumination problem by using a continuous wave (cw) laser radar to illuminate the scene. An LDRI unit is able to provide the reflectance imagery and range imagery simultaneously, with a pixel-by-pixel corresponding relationship.
The LDRI is a known technology as illustrated in the following references:
(A) Lin, C. F., Modern Navigation, Guidance, and Control Processing. Englewood Cliffs, N.J., Prentice-Hall, 1990.
(B) Lin, C. F., Advanced Control System Design. Englewood Cliffs, N.J., Prentice-Hall, 1993.
(C) Pecina, Jose N., Mike Snyder, Clyde Sapp, Kevin Crosby, Vincent Elliott, Premkumar Saganti, Greg Byrne, and Mike Gaunce, xe2x80x9cDynamic of the solar array motion: an image analysis approach,xe2x80x9d 1998 SEM Spring Conference on Experimental and Applied Mechanics, Houston, Tex. Jun. 1-3, 1998.
(D) James, George, III, David Zimmerman, Mike Grygier, George Studor, Jose N. Pecina, Robert Nellums, xe2x80x9cDevelopment of non-contact sensors and data analysis tools for ISS structural dynamics,xe2x80x9d AIAA 1999 Annual Technical Symposium. Developing Space Operations, Technology, and Utilization, Houston, Tex. May, 27-31.
(E) Press, W. H., S. A. Teukosky, W. T. Vetterling, and B. P. Flannery. Numerical Recipes in C: The art of Scientific Computing, Second Edition. Cambridge University Press, 1992.
(F) Studor, George, xe2x80x9cLaser Dynamic Range Imager Space Shuttle Flight Demonstration,xe2x80x9d NASA JSC, Houston, Tex. 77058, Structural Mechanics Report, 1998.
(G) Gelb, A. Applied Optimal Estimation. The MIT Press, 1974.
(H) Bierman, G. J. Factorization Methods for Discrete Sequential Estimation. Academic Press, 1977.
(I) Park, P., and T. Kailath. xe2x80x9cNew square root algorithms for Kalman filtering,xe2x80x9d IEEE Trans. Automatic Control, Vol. 40, No. 5, pp. 895-899, 1995.
(J) Golub, G. H., and C. F. Van Loan. Matrix Computations. Johns Hopkins University Press, 1983.
(K) Schmitt, R. L., R. J. Williams, and J. D. Matthews, xe2x80x9cHigh frequency scannerless imaging laser radar for industrial inspection and measurement applications,xe2x80x9d Sandia Report, SAND96-2739, UC-906, 1996.
The Laser Dynamic Range Imager (LDRI) is a dynamic version of the Scannerless Range Imager (SRI) and the Point Tracking (PT) algorithm. The SRI provides the range measurement from the laser unit to the field of view for far or near inspection distances, but it functions only on statics scenes. The Point Tracking (PT) software package provides the cross-plane time history motion, while a dynamic adaptation of the SRI generates the range measurements from the laser unit to the field of view. The advantage of the LDRI over the conventional photogrammetric methods resides in the feasibility in obtaining, simultaneously, the 3-D motion of multiple points without the necessity of using multiple cameras and specific targets. The resolution of the position of a point is dramatically improved, and the elimination of special illuminating conditions in the scene are unnecessary. Commercial applications exist in flight vehicle docking automated navigation, flight refueling, precision materials fabrication, collision avoidance, and modal analysis.
It""s still challenging to provide a processing method for the LDRI to realize the potential advantages of the LDRI.
A main objective of the present invention is to provide a three-dimensional (3D) relative positioning and tracking process utilizing the laser dynamic range imager (LDRI), wherein the reflectance imagery and range imagery are processed to simultaneously obtain the 3-D motion of multiple points of a target without the necessity of using multiple cameras and specific targets.
Another objective of the present invention is to provide a three-dimensional (3D) relative positioning and tracking process utilizing the laser dynamic range imager (LDRI), wherein the reflectance imagery and range imagery are further processed to obtain the relative attitude of the target with respect to the LDRI""s carrier.
Another objective of the present invention is to provide a three-dimensional (3D) relative positioning and tracking process utilizing the laser dynamic range imager (LDRI), wherein a practical focal length determination algorithm is disclosed for the Laser Dynamic Range Imager (LDRI) imagery, which does not require any control points. Focal length determination enables the translation of each pixel in the LDRI range imagery into the world coordinates in Cartesian representation.
Another objective of the present invention is to provide a three-dimensional (3D) relative positioning and tracking process utilizing the laser dynamic range imager (LDRI), wherein the world coordinates in Cartesian representation of the imagery enables to carry out orientation determination, which in turn aids the point tracking to project the trajectory in the world coordinate system. This provides a means to aid the intensity image processing by the range image processing, which is otherwise impossible without the utilization of the LDRI images.